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  1. 24 2月, 2017 1 次提交
  3. 23 2月, 2017 2 次提交
  5. 17 2月, 2017 1 次提交
  7. 14 1月, 2017 1 次提交
    • M
      sched/cputime, s390: Implement delayed accounting of system time · b7394a5f
      由 Martin Schwidefsky 提交于 
      The account_system_time() function is called with a cputime that
occurred while running in the kernel. The function detects which
context the CPU is currently running in and accounts the time to
the correct bucket. This forces the arch code to account the
cputime for hardirq and softirq immediately.

Such accounting function can be costly and perform unwelcome divisions
and multiplications, among others.

The arch code can delay the accounting for system time. For s390
the accounting is done once per timer tick and for each task switch.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
[ Rebase against latest linus tree and move account_system_index_scaled(). ]
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1483636310-6557-10-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      b7394a5f
  9. 17 11月, 2016 1 次提交
  11. 16 11月, 2016 3 次提交
  13. 15 11月, 2016 1 次提交
  15. 11 11月, 2016 2 次提交
  17. 17 10月, 2016 1 次提交
    • H
      s390/dumpstack: restore reliable indicator for call traces · d0208639
      由 Heiko Carstens 提交于 
      Before merging all different stack tracers the call traces printed had
an indicator if an entry can be considered reliable or not.
Unreliable entries were put in braces, reliable not. Currently all
lines contain these extra braces.

This patch restores the old behaviour by adding an extra "reliable"
parameter to the callback functions. Only show_trace makes currently
use of it.

Before:
[    0.804751] Call Trace:
[    0.804753] ([<000000000017d0e0>] try_to_wake_up+0x318/0x5e0)
[    0.804756] ([<0000000000161d64>] create_worker+0x174/0x1c0)

After:
[    0.804751] Call Trace:
[    0.804753] ([<000000000017d0e0>] try_to_wake_up+0x318/0x5e0)
[    0.804756]  [<0000000000161d64>] create_worker+0x174/0x1c0

Fixes: 758d39eb ("s390/dumpstack: merge all four stack tracers")
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      d0208639
  19. 20 6月, 2016 2 次提交
    • D
      s390/mm: remember the int code for the last gmap fault · 4a494439
      由 David Hildenbrand 提交于 
      For nested virtualization, we want to know if we are handling a protection
exception, because these can directly be forwarded to the guest without
additional checks.
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
      4a494439
    • M
      s390/mm: add shadow gmap support · 4be130a0
      由 Martin Schwidefsky 提交于 
      For a nested KVM guest the outer KVM host needs to create shadow
page tables for the nested guest. This patch adds the basic support
to the guest address space (gmap) code.

For each guest address space the inner KVM host creates, the first
outer KVM host needs to create shadow page tables. The address space
is identified by the ASCE loaded into the control register 1 at the
time the inner SIE instruction for the second nested KVM guest is
executed. The outer KVM host creates the shadow tables starting with
the table identified by the ASCE on a on-demand basis. The outer KVM
host will get repeated faults for all the shadow tables needed to
run the second KVM guest.

While a shadow page table for the second KVM guest is active the access
to the origin region, segment and page tables needs to be restricted
for the first KVM guest. For region and segment and page tables the first
KVM guest may read the memory, but write attempt has to lead to an
unshadow.  This is done using the page invalid and read-only bits in the
page table of the first KVM guest. If the first guest re-accesses one of
the origin pages of a shadow, it gets a fault and the affected parts of
the shadow page table hierarchy needs to be removed again.

PGSTE tables don't have to be shadowed, as all interpretation assist can't
deal with the invalid bits in the shadow pte being set differently than
the original ones provided by the first KVM guest.

Many bug fixes and improvements by David Hildenbrand.
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
      4be130a0
  21. 13 6月, 2016 1 次提交
    • H
      s390/cpuinfo: show dynamic and static cpu mhz · 097a116c
      由 Heiko Carstens 提交于 
      Show the dynamic and static cpu mhz of each cpu. Since these values
are per cpu this requires a fundamental extension of the format of
/proc/cpuinfo.

Historically we had only a single line per cpu and a summary at the
top of the file. This format is hardly extendible if we want to add
more per cpu information.

Therefore this patch adds per cpu blocks at the end of /proc/cpuinfo:

cpu             : 0
cpu Mhz dynamic : 5504
cpu Mhz static  : 5504

cpu             : 1
cpu Mhz dynamic : 5504
cpu Mhz static  : 5504

cpu             : 2
cpu Mhz dynamic : 5504
cpu Mhz static  : 5504

cpu             : 3
cpu Mhz dynamic : 5504
cpu Mhz static  : 5504

Right now each block contains only the dynamic and static cpu mhz,
but it can be easily extended like on every other architecture.

This extension is supposed to be compatible with the old format.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NSascha Silbe <silbe@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      097a116c
  23. 21 4月, 2016 2 次提交
    • M
      s390/fpu: allocate 'struct fpu' with the task_struct · 3f6813b9
      由 Martin Schwidefsky 提交于 
      Analog to git commit 0c8c0f03
"x86/fpu, sched: Dynamically allocate 'struct fpu'"
move the struct fpu to the end of the struct thread_struct,
set CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and add the
setup_task_size() function to calculate the correct size
fo the task struct.

For the performance_defconfig this increases the size of
struct task_struct from 7424 bytes to 7936 bytes (MACHINE_HAS_VX==1)
or 7552 bytes (MACHINE_HAS_VX==0). The dynamic allocation of the
struct fpu is removed. The slab cache uses an 8KB block for the
task struct in all cases, there is enough room for the struct fpu.
For MACHINE_HAS_VX==1 each task now needs 512 bytes less memory.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      3f6813b9
    • G
      s390/mm: fix asce_bits handling with dynamic pagetable levels · 723cacbd
      由 Gerald Schaefer 提交于 
      There is a race with multi-threaded applications between context switch and
pagetable upgrade. In switch_mm() a new user_asce is built from mm->pgd and
mm->context.asce_bits, w/o holding any locks. A concurrent mmap with a
pagetable upgrade on another thread in crst_table_upgrade() could already
have set new asce_bits, but not yet the new mm->pgd. This would result in a
corrupt user_asce in switch_mm(), and eventually in a kernel panic from a
translation exception.

Fix this by storing the complete asce instead of just the asce_bits, which
can then be read atomically from switch_mm(), so that it either sees the
old value or the new value, but no mixture. Both cases are OK. Having the
old value would result in a page fault on access to the higher level memory,
but the fault handler would see the new mm->pgd, if it was a valid access
after the mmap on the other thread has completed. So as worst-case scenario
we would have a page fault loop for the racing thread until the next time
slice.

Also remove dead code and simplify the upgrade/downgrade path, there are no
upgrades from 2 levels, and only downgrades from 3 levels for compat tasks.
There are also no concurrent upgrades, because the mmap_sem is held with
down_write() in do_mmap, so the flush and table checks during upgrade can
be removed.
Reported-by: NMichael Munday <munday@ca.ibm.com>
Reviewed-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      723cacbd
  25. 23 2月, 2016 2 次提交
    • H
      s390/dumpstack: merge all four stack tracers · 758d39eb
      由 Heiko Carstens 提交于 
      We have four different stack tracers of which three had bugs. So it's
time to merge them to a single stack tracer which allows to specify a
call back function which will be called for each step.

This patch changes behavior a bit:

- the "nosched" and "in_sched_functions" check within
  save_stack_trace_tsk did work only for the last stack frame within a
  context. Now it considers the check for each stack frame like it
  should.

- both the oprofile variant and the perf_events variant did save a
  return address twice if a zero back chain was detected, which
  indicates an interrupt frame. The new dump_trace function will call
  the oprofile and perf_events backends with the psw address that is
  contained within the corresponding pt_regs structure instead.

- the original show_trace and save_context_stack functions did already
  use the psw address of the pt_regs structure if a zero back chain
  was detected. However now we ignore the psw address if it is a user
  space address. After all we trace the kernel stack and not the user
  space stack. This way we also get rid of the garbage user space
  address in case of warnings and / or panic call traces.

So this should make life easier since now there is only one stack
tracer left which we can break.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      758d39eb
    • H
      s390: add current_stack_pointer() helper function · 76737ce1
      由 Heiko Carstens 提交于 
      Implement current_stack_pointer() helper function and use it
everywhere, instead of having several different inline assembly
variants.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      76737ce1
  27. 19 1月, 2016 1 次提交
  29. 11 1月, 2016 1 次提交
  31. 27 11月, 2015 1 次提交
  33. 03 11月, 2015 1 次提交
  35. 27 10月, 2015 2 次提交
  37. 16 10月, 2015 1 次提交
  39. 14 10月, 2015 4 次提交
  41. 29 7月, 2015 1 次提交
  43. 22 7月, 2015 3 次提交
    • H
      s390/kernel: lazy restore fpu registers · 9977e886
      由 Hendrik Brueckner 提交于 
      Improve the save and restore behavior of FPU register contents to use the
vector extension within the kernel.

The kernel does not use floating-point or vector registers and, therefore,
saving and restoring the FPU register contents are performed for handling
signals or switching processes only.  To prepare for using vector
instructions and vector registers within the kernel, enhance the save
behavior and implement a lazy restore at return to user space from a
system call or interrupt.

To implement the lazy restore, the save_fpu_regs() sets a CPU information
flag, CIF_FPU, to indicate that the FPU registers must be restored.
Saving and setting CIF_FPU is performed in an atomic fashion to be
interrupt-safe.  When the kernel wants to use the vector extension or
wants to change the FPU register state for a task during signal handling,
the save_fpu_regs() must be called first.  The CIF_FPU flag is also set at
process switch.  At return to user space, the FPU state is restored.  In
particular, the FPU state includes the floating-point or vector register
contents, as well as, vector-enablement and floating-point control.  The
FPU state restore and clearing CIF_FPU is also performed in an atomic
fashion.

For KVM, the restore of the FPU register state is performed when restoring
the general-purpose guest registers before the SIE instructions is started.
Because the path towards the SIE instruction is interruptible, the CIF_FPU
flag must be checked again right before going into SIE.  If set, the guest
registers must be reloaded again by re-entering the outer SIE loop.  This
is the same behavior as if the SIE critical section is interrupted.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      9977e886
    • H
      s390/kernel: introduce fpu-internal.h with fpu helper functions · 904818e2
      由 Hendrik Brueckner 提交于 
      Introduce a new structure to manage FP and VX registers. Refactor the
save and restore of floating point and vector registers with a set
of helper functions in fpu-internal.h.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      904818e2
    • H
      s390/kernel: move EX_TABLE macros to linkage.h header file · 2e54dc3c
      由 Hendrik Brueckner 提交于 
      Move the EX_TABLE macro definitions from the processor.h to the linkage.h
header file.  It helps to reduce circular header file dependencies.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      2e54dc3c
  45. 25 3月, 2015 1 次提交
    • H
      s390: remove 31 bit support · 5a79859a
      由 Heiko Carstens 提交于 
      Remove the 31 bit support in order to reduce maintenance cost and
effectively remove dead code. Since a couple of years there is no
distribution left that comes with a 31 bit kernel.

The 31 bit kernel also has been broken since more than a year before
anybody noticed. In addition I added a removal warning to the kernel
shown at ipl for 5 minutes: a960062e ("s390: add 31 bit warning
message") which let everybody know about the plan to remove 31 bit
code. We didn't get any response.

Given that the last 31 bit only machine was introduced in 1999 let's
remove the code.
Anybody with 31 bit user space code can still use the compat mode.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      5a79859a
  47. 29 1月, 2015 1 次提交
  49. 28 11月, 2014 1 次提交
  51. 09 10月, 2014 2 次提交
    • M
      s390: add support for vector extension · 80703617
      由 Martin Schwidefsky 提交于 
      The vector extension introduces 32 128-bit vector registers and a set of
instruction to operate on the vector registers.

The kernel can control the use of vector registers for the problem state
program with a bit in control register 0. Once enabled for a process the
kernel needs to retain the content of the vector registers on context
switch. The signal frame is extended to include the vector registers.
Two new register sets NT_S390_VXRS_LOW and NT_S390_VXRS_HIGH are added
to the regset interface for the debugger and core dumps.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      80703617
    • M
      s390/idle: consolidate idle functions and definitions · b5f87f15
      由 Martin Schwidefsky 提交于 
      Move the C functions and definitions related to the idle state handling
to arch/s390/include/asm/idle.h and arch/s390/kernel/idle.c. The function
s390_get_idle_time is renamed to arch_cpu_idle_time and vtime_stop_cpu to
enabled_wait.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      b5f87f15